Miniature bandpass filter constructions based on a novel dual-mode suspended stripline resonator are proposed. Because of a special structure of the resonator, the frequencies of two first oscillation modes may be brought closer together. That allows realizing narrowband filters with the wide upper stopband. The filters have low insertion loss in the passband at small dimensions. Several transmission zeros substantially improve the filter performance. The derived coupling coefficients account for some features in the frequency response of the filter. The second-order and fourth-order filters with transmission zeros have been fabricated and measured.
2. Menzel, W. and A. Balalem, "Quasi-lumped suspended stripline filters and diplexers," IEEE Trans. Microw. Theory Tech., Vol. 53, 3230-3237, 2005.
3. Lin, L.-J., M.-H. Ho, and W.-Q. Xu, "Design of compact suspended stripline bandpass filters with wide stopband," Microwave and Optical Technology Letters, Vol. 50, 865-868, 2008.
4. Kim, J.-S., N.-S. Kim, W.-G. Moon, and G.-B. Lee, "A novel broadband suspended substrate stripline filter using dual-mode resonators," IEEE 19th International Symposium on Personal, Indoor and Mobile Radio Communications, 1-4, Cannes, 2008.
5. Menzel, W. and M. Berry, "Quasi-lumped suspended stripline filters with adjustable transmission zeroes," 2004 IEEE MTT-S Int. Microwave Symposium Digest, 1601-1604, Fort Worth, 2004.
6. Dovbysh, I. A. and V. V. Tyurnev, "Resonant properties of double-wire suspended stripline resonator," 15th Int. Crimean Conf. \Microwave & Telecommunication Technology, 487-489, Sevastopol, 2005.
7. Belyaev, B. A., A. A. Leksikov, V. V. Tyurnev, and A. V. Kazakov, "Strip-line filter with suspended substrate," 15th Int. Crimean Conf. \Microwave & Telecommunication Technology, 506-507, Sevastopol, 2005.
8. Belyaev, B. A., A. A. Leksikov, A. M. Serzhantov, and V. V. Tyurnev, "Miniature suspended-substrate bandpass filter," Progress In Electromagnetics Research C, Vol. 15, 219-231, 2010.
9. Zhang , Y., , K. A. Zaki, A. J. Piloto, and J. Tallo, "Miniature broadband bandpass filters using double-layer coupled stripline resonators," IEEE Trans. Microw. Theory Tech., Vol. 54, 3370-3377, 2006.
10. Beljaev , B. A., A. A. Leksikov, A. M. Serzhantov, F. G. Sukhin, and A. V. Izotov, "Strip-line bandpass filter," RU Patent 22402121, Oct. 20, 2010.
11. Tyurnev, V. V., "Coupling coe±cients of resonators in microwave filter theory," Progress In Electromagnetics Research B, Vol. 21, 47-67, 2010.
12. Belyaev, B. A., A. A. Leksikov, M. M. Titov, and V. V. Tyurnev, "A microstrip array filter with irregular resonators," J. of Communications Technology and Electronics, Vol. 47, 848-855, 2002.
13. Shi, J. and Q. Xue, "Dual-band and wide-stopband single-band balanced bandpass ¯lters with high selectivity and common-mode suppression," IEEE Trans. Microw. Theory Tech., Vol. 58, 2203-2212, 2010.
14. Lu, J.-C., C.-K. Liao, and C.-Y. Chang, "Microstrip parallel-coupled ¯lters with cascade trisection and quadruplet responses," IEEE Trans. Microw. Theory Tech., Vol. 56, 2101-2110, 2008.
15. Deng, P.-H. and P.-T. Chiu, "New bandpass filters using half-wavelength and branch-line resonators," Progress In Electromagnetics Research C, Vol. 16, 241-249, 2010.